Spring structure



April 22, 1941. E. s. TALLMADGE SPRING STRUCTURE Filed June 3, 1940 2Sheets-Sheet 1 INVENTOR. EVERETT s. TALLMADGE WM M 1 ATTORNEYS April 22,1941.

E. S. TALLMADGE SPRING STRUCTURE Filed June 3, 1940 2 Sheets-Sheet 2 l6l7 l8 FIG.'5.

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INVENTOR. VERETT s. TALLMADGE A T TORNE YS Patented Apr. 22, 1941 SPRINGSTRUCTURE Everett S. Tallmadge, Robblnsdale, Minn., assignor to EdwardMinn.

W. Schlappritzi, Minneapolis,

Application June 3, 1940, Serial No. 338,623

11 Claims.

This invention relates generally to spring structures and refers moreparticularly to multiple leaf spring structures.

One of the essential objects of the invention is to provide a springstructure of this type wherein supporting or secondary spring leaves ofpredetermined configuration are used against or in combination withlonger spring leaves, either main or secondary, to reinforce the main oradjacent leaves so that the structure as a whole will function properlywithout breakage or failure to carry and cushion a given load.

Another object is to provide a spring struc-- ture wherein the secondaryspring leaf reinforcement bridges or spans the point or points of themain or adjacent leaves where breakage or failure would ordinarily occurand is provided at its free end with means for definitely relieving themain or adjacent leaves of any concentration of strain or of anypiercing or shearing action tending to cause failure or breakage.

Another object is to provide a spring structure wherein the means justmentioned enhances the pliability, flexibility and spring action of theleaves so that the structure functions better and more efficiently. 1

Another object is to provide a spring structure that is simple inconstruction, economical to manufacture, and reliable in operation.

Other objects, advantages and novel details of construction of thisinvention will be made more apparent as this description proceeds,especially when considered in connection with the accompanying drawings,wherein:

Figure 1 is a perspective view of a spring structure embodying myinvention;

Figure 2 is a fragmentary perspective view thereof;

Figure 3 is a fragmentary bottom plan view of the structure shown inFigure 2;

Figure 4 is a sectional view taken substantially on the line L4 ofFigure 3;

Figure 5 is a plan view of a slight modification;

Figure 6 is a view similar to Figure 5 but show-- ing anothermodification;

Figure 7 is a view similar to Figures 5 and 6 but showing a furthermodification;

Figures 8 and!) are fragmentary plan views of a blank from which thereinforcing leaves are formed, and showing the manner in which suchreinforcing leaves can be cut from the blank.

The reinforcement mentioned is intended primarily for use as a supportfor main leaves of bed springs, cushion springs, etc., however it isapplicable to any leaf spring structure wherein supporting or secondaryspring leaves are desired and may be any suitable shape or configurationdepending upon the shape or configuration of the main or adjacent springleaves with which it is used.

In the accompanying drawings, A is the main frame, B is the auxiliaryframe, C are the main spring leaves, and D are the secondary springleaves of a spring structure embodying my invention.

As shown, the main frame A is substantially rectangular shape and isformed of tubing. The elements III are reinforcing bars extendingbetween opposite sides of the frame, while the elements l I arereinforcing bars extending between opposite ends of the frame.

The auxiliary frame B substantially conforms in configuration to themain frame and is substantially parallel thereto. Preferably thisauxiliary frame is formed of strips of spring steel and includesnumerous tie bars l2 that extend in pairs between opposite sides of saidframe.

The main spring leaves C are substantially cshape in configuration andare arranged in rows along the reinforcing bars H between the main andauxiliary frames A and B. The lower ends of such leaves C are rigidlysecured by rivets [3 or the like to the reinforcing bars II, while theupper ends of said leaves are secured by rivets I4 to the tie bars l2.Preferably each spring leaf C is substantially equal in width and issecured to a pair of tie bars l2.

As shown, the secondary spring leaves D are on the underside of the mainleaves C and extend between the latter and the reinforcing bars ll.However, it is apparent that such leaves D may be used on the upperside,inside, outside, or in surface-to-surface contact with any portiondesired of the main or adjacent leaves C. In the present instance, therivets I: that serve as securing means for the main leaves C also serveas securing means for the secondary leaves D. By referring to Figures 2and 3, it will be noted that the secondary leaves D are narrower thanbut are centered with respect to the main leaves C, however it is to beunderstood that such secondary leaves may if desired be equal in widthto or wider than the main leaves C. By referring to Figure 4 it will benoted that the secondary leaves D conform in curvature to and bearfirmly in surface-to-surface relation against the main leaves C. It willalso be noted that the secondary leaves D are of sufiicient length tobridge or span the critical point of the main 6 I have illustratedanother modification wherein' the three tongues ll, 20 and II,respectively, are not uniform in configuration or length. Thisdifference in length gives greater distribution of strains. In Figure 7I have illustrated another modification wherein only two symmetricaltongues 22 and 23, respectively, are employed. In each instance,however, the multiple tongues distribute the strains across the width ofthe supported leaves C and thereby eliminate or reduce localizedstresses and increase the durability or the load that can be safelycarried. Actually the multiple tongue feature of the secondary.

leaves provides more flexibility since the multiple tongues'are morepliable and enhance at spaced points the spring action in the structure.Thus, there is no concentration of strain at or near any one point ofthe secondary leaves tending to cause failure in the supported leaves.Likewise, there is no tendency-of the secondary leaves to pierce orpunch through the supported leaves or to produce any shearing action. Aslong'as the secondary leaves D have two or more tongues at their freeends and are of sufficient length to bridge or span the critical pointsof the main spring leaves C, the secondary leaves D and the tongues atthe free ends thereof may be any shape desired.

Due to the multiple tongue feature, the sec, ondary leaves D may bereadily formed from blanks or strip stock with little or no waste, as

illustrated in Figures 8 and 9. By referring to these figures it will benoted that substantially one zigzag cut across the blank will providetwo adjacent sets of tongues. The blanks may then be cut at 30 and 3|(Figure 8), or'at l2 and 33 (Figure 9) as desired, to provide thesecondary leaves. Thus, in making leaves with tongues at one endthereof, the. material'can be conserved as the pieces can be blanked inpairs without waste of material from the notches or recesses between thetongues. When blanked in this way from material having a grain parallelwith the side edges of the material, as, for example, strip steel, thelongitudinal direction of the grain is kept within the tongues,consequently they are materially strengthened.

What I claim as my invention is:

1. A spring structure having upper and lower frame members, and two leafsprings secured in overlapping relation to one of said frame. membersand extending toward the other of said frame members, one of said leafsprings being substantially C-shape in configuration and secured to theother of said frame members, the second leaf spring havingsurface-'to-surface contact throughout its length with the C-shapedspring and having a plurality of laterally spaced tongues at its freeend.

2. A spring structure having upper and lower framemembers, and two leafsprings secured in I frame members, one of said leaf springs beingsubstantially c-shape in configuration and secured to the other of saidframe members, the second leaf spring having surface-to-surface contactthroughout its length with the c-shaped spring and terminating in aplurality of laterally spaced substantially triangular shaped tongues.

3. A spring structure having upper and lower frame members, a leafspring extending between and secured to said frame members, and asecondary leaf spring having" surface-to-surface' contact throughout itslength with the first mentioned spring, said secondary spring beingsecured to one of said frame members and free of the other, the free endof said secondary spring consisting of a plurality of laterally spacedpointed tongues.

4. A spring structure having upper and lower frame members, a leafspring extending between and secured to said frame members, and asecondary leaf spring having s'urface-to-surfacecontact throughout itslength with the first mentioned spring, said secondary spring beingsecured to one of saidframe members and free of the other, the free endof said secondary spring having a plurality of laterally spaced pliableportions.

5. A spring structure having upper and lower frame members, a leafspring extending between and terminally secured to said frame members,and a secondary leaf spring secured to the lower frame member and havingsurface-to-surface contact throughout its length with the firstmentioned leaf spring, the secondary spring spanning a critical point ofthe first mentioned spring and provided between said point and the upperframe member with a free end having a plurality of laterally spacedsubstantially triangular shaped tongues.

6. A spring structure having upper and lower frame members, a leafspring extending between and secured to said frame members, and asecondary leaf spring secured to one of said frame members and free ofthe other, said secondary spring being in surface-to-surface contactthroughout its length with the leaf spring aforesaid and provided at itsfree end with a plurality of pliable substantially triangular portions.

7. A spring structure having upper and lower frame members, a leafspring extending between and terminally secured to said. frame members,and a secondary leaf spring having surface-tosurface contact throughoutits length with theleaf spring aforesaid and spanning a critical pointthereof adjacent the lower frame member, :said secondary spring beingprovided between said frame members with a free end having endwiseprojecting laterally spaced tongues.

8. A spring structure having upper and lower frame members, a leafspring extending between and secured to said frame members, asecondaryleaf spring having surface-to-surface contact throughout its lengthwithand spanning a ,critical point of the spring aforesaid,-thesecondary spring being secured to oneof the frame members and free ofthe other, the free end of the secondary spring consisting of aplurality of laterally spaced pliable endwise projecting substantiallytriangular portions for relieving the first mentioned spring of anyconcentration of strain.

9. A spring structure having upper and lower frame members, and two leafsprings secured in overlapping relation to one of said frame members andextending toward the other of said frame memberaoneof said leaf springsbeing substantially c-shape in configuration and secured to the other ofsaid frame members, the second leaf spring having surface-to-surfacecontact throughout its length with the c-shaped spring and provided atits free end with a plurality of laterally spaced tongues, the secondleaf spring spanning a critical point of the c shaped spring adjacentthe lower frame member and relieving the c-shaped spring ofconcentration of strains or piercing or shearingaction at said criticalpoint. 7

10. A spring structure having upper and lower frame members, a main leafspring extending between and secured to said frame members, and asecondary leaf spring having surface-tosurface contact throughout itslength with the main spring, the secondary spring being secured at oneend to the lower frame member and provided between said frame memberswith a free end having endwise projecting laterally spaced 20 tongues,said secondary spring spanning a critical point of the main springadjacent the lower frame member and relieving the main spring ofconcentration of strains or piercing or shearing action at said criticalpoint. 7

- -11. A spring structure having upper and lower frame members, a mainleaf spring extending between and secured to said frame members, and asecondary leaf spring of less length than the main spring havingsurface-to-surface contact throughout its length with the main spring,the secondary spring being secured at one end to one of the elementsaforesaid and provided between said frame members with a free end havinglaterally spaced tongues, said secondary spring spanning a criticalpoint of the main spring adiacent the lower frame member and relievingthe main spring of concentration of strains or piercing or shearingaction at said critical point.

8. TAILMADGE.

